Origin of the name MAPONUS.
Etymology of the
name MAPONUS.
Meaning of the baby name MAPONUS.

MAPONUS.
The same as Celtic Maponos
(q.v.), another name for the Gaulish Apollo, meaning "the great
youth."

Maponus,
"the great youth," was one of the names given by the ancient
Celts to a god of healing who presided over thermal springs and
corresponded to Apollo
(q.v.). Another name for the god was Grannus
(q.v.) The name Maponus survived in Mabon,
one of the heroes in Welsh mythology. Mabon, the son of Modron
(probably equivalent to Matrona), appears as a companion of King Arthur.
(An Encyclopaedia of Religions, Canney, 1921)